A year ago, Matt Olson claimed the RBI crown for the Class A Beloit Snappers, beating out Chris Bostick and Renato Nunez. This season, the race is on between Olson and Nunez for another prestigious power mark.

Olson and Nunez, he A's No. 2 and 3 prospects, respectively, both homered and combined to drive in seven runs Saturday night as Class A Advanced Stockton outslugged San Jose, 13-7.

With about a month left in the Minor League regular season, Nunez kept pace with Olson for the California League home run lead. The 20-year-old third baseman belted a first-inning grand slam with Olson aboard, part of a seven-run outburst as Stockton raced out to a big early lead.

"My message was that we just had a good opportunity moving forward with another game tomorrow to really put a hurting on their bullpen," Ports manager Ryan Christenson said. "That was the motivation I tried to get across, to continue to grind out at-bats and see how many guys we could get into the game."

In the fourth, Olson greeted reliever Ian Gardeck with a leadoff homer, his 31st, then hit back-to-back doubles with Nunez in the sixth to extend Stockton's lead to 11-0.

"It's been fun to watch those guys all year," Christenson said. "When they're clicking at the same time, it's trouble for opposing pitchers. Nunez has really had his power stroke going here in the second half. I heard today that was his 18th home run in the second half. He's really locked in, and the kid is so strong, I think he got jammed on the grand slam he hit tonight. It's fun to watch."

Nunez has been a revelation in the second half for the Ports. Over 38 games since the All-Star break, he's batting .331/.383/.726 with 18 homers and 52 RBIs. His power numbers are especially impressive when compared with his nine homers and 29 RBIs in 60 games in the first half. Stockton is 27-15 and three games ahead of second-place San Jose in the California League North Division second-half race.

"He made a couple small adjustments to start the second half," Christenson said. "They've really paid dividends for him as far as what he's been able to do production-wise for us. He obviously is a big part of what we do as an offense in that four-hole."

Olson is coming off a month in which he batted .233, his lowest mark in any month this season. But the 20-year-old right fielder's three-hit night on Saturday was his first since July 18 and second since June 19.

"He's been consistent for us," Christenson said. "Obviously, the home runs are there. The average isn't eye-popping, but I think his on-base percentage is because he's walked so many times. He's approaching 100 walks at this point in the season. It's been huge for us, and that's why I feel comfortable keeping him in that three-hole in front of Nunez. He gets on base a lot, just like he did there in the first inning tonight. He drew the walk to load the bases and Nunez hit the home run for the grand slam."

Olson is four homers ahead of Nunez in the Cal League home run race. His next-closest challenger, High Desert's Jabari Henry, checks in with 23.

"I saw [the competitiveness] last year as they were battling for an RBI title and then this year with Nunez coming on strong, chasing Olson down for the home run title for the league," Christenson said. "I definitely think that they do feed off of each other. They have a great friendship and competitive relationship when it comes to that. I think they feed off of each other, and it pushes their performance up a notch because of it."

Trailing by 11 runs heading to the bottom of the sixth, the Giants began to make things interesting by scoring six times. Leadoff man Jesus Galindo finished 3-for-5 with a triple, two doubles, two RBIs and two runs scored.

Stockton's Josh Bowman (4-7) won his second straight start after allowing four runs on eight hits and a walk with three strikeouts in 5 2/3 innings.

San Jose starter Matt Lujan (4-2) was roughed up for seven runs -- six earned -- on four hits and three walks without recording an out as his ERA climbed from 3.55 to 4.97.

Tyler Maun is a contributor to MiLB.com. Follow him on Twitter @TylerMaun. This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.